Attachment plug



Aug 12, 1924; I 1,504,655

D. N. THOMPSON ATTACHMENT PLUG Filed Aug. 25 1919 i I Z wuautozlPatented Aug... 12, 124.

DON N. THOMPSON, SCU'SE, NEW Y0.

ATTACHMENT PLUG.

Application filed August 25, 1919. Serial No. 319,645.

Toall whom it may concern Beit known that I, 'DoN N. Tnomrsou, a

' citizen of the United States', and resident/of Syracuse, in the countyof Onondaga, State of New York, have invented certain new and usefulImprovements in Attachment Plugs, of which the following is aspecification.

Thepresent invention relates to electrical connectors and particularlyto separable at tachm'ent plugs adapted to be used in connecting branchcircuits, especially lamp circuits, with main supply lines or circuits.

The objects of the invention are to provide an article of 'this classwhich is light and strong, has aminimum number of parts therebypromoting ease of manufacture and assembly, in which the spring contactsare protected by the insulating base so that it is impossible for anyone handling the plugs to bend and displace them or to establishconnection between them through his fingers, thereby sustaining anelectrical shock, and in which the openings in the plug which areprovided for the insertion of the contact blades of the cap areautomatically closed by the spring contacts to prevent the entrance ofdirtinto the hollow interior.

The invention will be fully disclosed in the following description whentaken in connection with the accompanying drawings in which:

Figure 1 is a longitudinal section of the plug, the cap being removed;

Iugure 2 is a top view of the plug base shown in Figure 1;

Figure 3 is a bottom view of the same, portions being removedj 7 Figure4 is a dis-assembled view. of the entire structure.

The base 10, the cap 11, and the button 12 are of any customaryinsulating material, and the metallic parts of the. lug are of brass,copper, or other suitab e material. The base 10 is provided withrecesses 13 and '14 on opposite sides of a central partition 15, and therecesses 13 and 14 communicate through openings 16 and 17 respectivelywith a central rectangular guide opening 18.

By means of a screw 19, having its head in a recess 20 in the centralpartition 15, the various metallic contacts and insulatingbutton 12 areattached to the base portion. The spring contact 21 has an o ning in itslower horizontal portion throng which the screw 19 passesand a nut 22holds this contact in position with its upper portion contained withinthe recess 13. The upper portion of the spring 21 is in the shape of aninverted U, one leg of which lies close to and is parallel with the wallof partition 15, while the other leg is downwardly and outwardlyinclined and has its end bearing a ainst the opposite wall of the recess13. he upper rounded portion of the spring lies adjacent the opening 16between the guide hole and the recess 13 and the springlis so designedthat it normally tends to old the upper rounded portion thereof in theopening to close the same, and its outer end by continually pressing onthe wall of the recess tends 7 0 to force the remainder of the springtoward the partition. The screw 19 has at its lower end a nut 22 whichcooperates with the screw in securing the button 12 and the shellcontact 23 to the base and which also serves as a center contact for theplug when the latter is screwed into a socket.

The shell contact 23 is of the usual construction and is clamped bymeans of the screw 19 and nut 22 between the insulating button 12 andthe base 10. To the upper en of the shell contact 23 is secured thespring contact 24 which is constructed exactly in the same manner as thespring contact 21 and designed to operate in'the same way to normallyclose the opening 17. The cap 11 is of the usual construction and hassecured thereto downwardly projecting contact blades 2/1 and 25 whichare adapted to be inserted through openings 16 and 17 into the recesses13 and 14: and to establish contact with the spring contacts therein.

In inserting the contact blades into the base the ends of the bladesafter passing through the openings 16 and 17 respectively strike therounded portions of spring contacts 21 and 24 and after forcing themradially outward a sufficient distance pass downwardl between the springcontacts and the insulating partition 15.

When the cap is seated the notches 26 in the contact blades are engagedby the lugs 27 on the contact springs and the cap is locked in positionagainst accidental movement.

While I have shown the contact springs 21 and 24 as hearing against boththe outer walls of the recesses and the walls of the partition, it willbe apparent that they may be otherwise arranged and still normallyminate in the bottom of the close the openings 16,17, hence I donotlimit" said button upwardly through said partition myself to theexact'form of the device as illustrated. 7

Having thus described the invention what is claimed as new and desiredto be secured by Letters Patent is:

1. A separable attachment plug comprising in combination, an insulatingbody having two spaced recesses terminating below the upper surface andseparated by a central partition and a single guide hole slightlyoverlapping at its end a'portion of the top of said recesses andextending to a plane below their upper ends, thus communicating withboth of said recesses, a contact in each of said recesses hearingagainst said partition up to its top and to the bottom of said guidehole and there bent outward from said partition.

2. A separable attachment plug comprising in combination, an insulatingbody having two spaced recesses therein at equal distances from its axisand a single centrally located guide hole overlapping a portion of saidrecesses slightly at its ends and extending below their upper ends thuscommunicating with both of said recesses, a spring contact in each ofsaid recesses extending outwardly and upwardly from the line wheretheadjacent walls of the recesses teride hole to the line where the topwalls 0 the recesses terminate in the end walls of the guide hole thusnormally closing the entrance openings leading into the recesses.

3. A separable attachment plug comprising in combination a substantiallycylindrical insulation body haying an elongated rectangular guideopening in the top thereof and a pairvof contact recesses open at thebottom, separated by a partition and having lateral and partiallongitudinal communication with said guide opening, an insulationbutton, a threaded contact shell fitting between and abutting at theends against the insulation body and the button, a central contactmember, a single member holdin all of said parts together and a pair 0spring contacts in said r'ecessesengaging said partition along the upperend thereof and having curved ends adapted to normally close theopenings between said contact recesses and said guide opening forthepurpose set forth.

4. A separable attachment plug comprising in combination an insulatingbod portion having two spaced recesses t erein separated-by a partitionand a single guide hole communicatin with both of said recesses throughopenings on opposite sides of said partition, a shell contact abuttingat its upper end said body around the open ends of said recesses, aninsulating button abutting the lower end of said shell, a connectingmember extending centrally from to a point below the bottom of saidguide hole and two spring contacts one of which is connected at itslower end to said connecting member below the body and extends upwardlytherefrom in one recess to its opening and the other of which is fixedat its lower end to said contact shell and extends upwardly in the otherrecess to its opening.

5. A separable attachment plug comprising in combination a body ofinsulating material having an elongated rectangular guide openingarranged centrally in its upper end and extending a short distancedownward, and having two similar separated lon itudinal contact recessesof the same widt as said rectangular guide opening extending attheir-facing sides under the ends of said opening a distance sli htlymore than the thickness of contact blades and,extending a materialdistance outwardly beyond the ends of said opening and terminating attheir upper ends slightly above the bottom of said guide opening wherebythe lane of the entrance connections or openlngs between said uideopening and recesses extends outwardly and upwardly at an angle, andspring contacts in said recesses extending substantially across them andcurved outwardly at their upper ends to lie in substantially the planeof said entrance connection and normally close it.

6. An attachment plug comprising in combination an insulating bodyhaving two recesses therein on opposite sides extending upwardly fromthe lower end to a point near the top and an elongated rectangular guideopening centrally arranged in the to with its ends slightly intersectingthe a jaeent edges of said recesses and extending slightly below theirupper ends thus joining them and forming communicating openings, a

shell contact fitting at its upper end said I body around the open ends0 said recesses, a button of insulating material fitting the lower endof said shell, a centrally arranged screw extending downwardly throughsaid body with its head engaging said body below the bottom of saidguide opening and centrally through said shell and button, and providedat its lower end with a nut for clamping said body shell and nuttogether, two spring contacts, one of which is connected at its lowerend to said screw below the body, extends upwardly in'one recess, and atlts upper end is bent outwardly at the opening into the guide opening,and the other of which is connected at its lower end to the upper end ofthe shell extending upwardly in the other recess and at its upper endbent outwardly at the opening into the guide opening.

In testimony whereof I aflix in signature,

DON N. THOKIPSON.

